See below listings for new unlocked iPhone 4. The new iPhone offers some new interesting features. On first place the iPhone 4 has 2 cameras - one on the back side and one on the front side. So with the function FaceTime there is an opportunity for video calls.
iPhone 4 offers now and multitasking. That is the first iPhone that offers that function. Now there will be possible for 2 or more applications to run at the same time on the phone. The multitasking is coming with the new operation system iOS 4.
There is also new display for iPhone called "Retina display" with better resolution (960x640 px @ 326 ppi).
But one of more important improvements is the battery. Now it allows between 6-7 hours conversations or 3G web browsing, 10 hours web browsing, using WiFi, 10 hours video play, 40 hours music play and 300 hours standby.